The concept of waves is fundamental due to its occurrence throughout the natural world. Because the concept occurs in so many places, students come to the classroom with prior knowledge, as well as misconceptions, about waves. Students have misconceptions about what is waving in a wave, what properties of the medium determine wave speed, and how waves interact with each other. In this article, the authors describe a project-enhanced unit on sound waves they they introduced to their students. The unit was implemented within an Industrial Electronics course of an inner-city, low-performing high school in Texas. The unit was aimed to have students gain conceptual understanding of sound waves and wave phenomena and the related trigonometric reasoning associated with sinusoidal curves and superposition of sinusoidal waves. (Contains 6 figures.)